In recent years, placing metal stents into biliary duct via the endoscope has been an important method of treatment of many malignant biliary strictures. Existing biliary metal stent delivery system contains a long outer sheath and an inner rod, the stent is preloaded in the cavity between the outer sheath and the inner rod. In the process of delivering a stent, it is essential to ensure that the inner rod and the stent are in the predetermined position relative to the stricture region while withdrawing the outer sheath. For neither the sheath nor the inner rod is fixed relative to the region of deploying the stent, it is required for the operator to closely cooperate with the assistant to control the relative movement of the inner rod and the sheath to maintain the stent without migration. Because the long outer sheath suffers friction of the operating channel of the endoscope, when the assistant pulling back the sheath, the operator needs to pull out the sheath from the operating channel at the same speed, otherwise it will cause the stent deviates from the predetermined site due to a relative motion moving the inner rod forward. Therefore, it is difficult to operate existing metal stent delivery devices. In this process, any slight mistake will deviate or even fall off the deployed the stent, and will even result in a surgical failure. Therefore, there is a need to reload the stent into the sheath and re-deploy the stent for the accurate stent positioning.
Therefore, they are demanding problems to be solved in the art: how to carry out a single-person operation, and how to simply and precisely deploy the stent to the target position after accurately locating the stent's position.